It is well known in the industry to use positive cutoff spouts or portioning devices to meter the amount of bulk food that is to be deposited into a container. In such a device, a pneumatically controlled ram combination or other reciprocating assembly is coupled to a plug piston located in a cylindrical tube having a food product inlet orifice positioned generally intermediate the stroke of the plug piston. The piston has a skirt to prevent the entry of food product into the tube when the piston face descends past the inlet orifice.
In operation, a control signal is sent to an actuator and causes the ram, and therefore the plug piston, to fully retract, thereby permitting food product to enter the portioning cylinder via the inlet orifice. At a specific time interval, another control signal is sent to the actuator and causes the plug piston to fully extend, thus ejecting the food product from the portioning cylinder and into whatever container was located below it. This cycle would be repeated until a desired end was reached.
This area of the art, however, was not without problems. Because some food products had high levels of tack, they would often times stick to the piston face and thereby not provide precisely metered or portioned food product. A solution to this problem involved using a hollow ram rod to connect the air cylinder with the plug piston and creating a foramenous piston face. In this manner, at the point of full piston extension, a short blast of compressed air would be introduced into the hollow ram rod which would exit from the foramenous piston face and dislodge the stuck food product. This pneumatic dislodgment assistance was often time used in conjunction with a short and very small stroke reciprocation prior to the return of the piston to its initial position. This physical dislodgment assistance also proved to be effective in overcoming the identified problem.
Even in view of these advances, however, dispensing problems associated with certain food products having high levels of tack or sinuous materials such as found in meat products persisted. In particular, sinuous materials would often lodge in the annular space between the piston circumference and skirt, and the portioning cylinder wall. This lodgment would cause partial blocking of the inlet orifice, or additional sticking of food product during the dispensing step.
In view of the foregoing, the need for an improvement in this area of technology is apparent. The present invention is intended to meet this need.